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Flashcards in Lecture Terms Deck (137):
1

axial skeleton

vertebral column, skull, ribs, sternum

2

appendicular skeleton

long limbs, pelvic and pectoral girdle

3

flexion angle

depends on functionality - flexing a muscle will happen if the flexor angle is DECREASED
cranial/caudal above the hock or manus
palmar/plantar/dorsal beneath it

4

Five recognized radiodensities

From radiolucent to radiopaque:
Air, Fat/Oil, Water/Soft Tissue, Bone, and Metal

5

Orthogonal angle

A perpendicular angle, necessary to get 3d information from two 2d images

6

Why are shoulder and scapula fx and luxations relatively uncommon?

Scapula is held close to the body and has a great deal of muscle padding. The shoulder has a very large articular surface - it is hard for it to get displaced.

7

Why are humeral and rad/ulna fx common?

Far from the body and more exposed
Meant to bear weight cranially/caudally not orthogonally.

8

Is luxation of the elbow usually medial or lateral?

Lateral. The capitulum and the lateral epicondyle of the humerus are both smaller than their medial counterparts.

9

How should luxation of the elbow be reset?

With the elbow flexed. The olecranon will be in the way otherwise.

10

luteinizing hormone (LH)

Hormone that surges 24 hours prior to ovulation. Causes the maturation the follicle/oocyte.

11

What is the progression of the maturation of the oocyte in the ovary?

Primordial follicle
Secondary follicle
Mature follicle
Ovulation
Corpora lutea

12

What are the major trends of progesterone and estrogen during proestrus?

estrogen decreases hyperbolically
progesterone increases hyperbolically

13

How long after breeding can the sperm fertilize the egg?

Species dependent.
Most: 4-6 days
Horses/Dogs: 7-10 days

14

When does the oocyte's first mitotic division takes place and what is formed?

After sperm are in place but before fertilization. Creates the female pronucleus and the two polar bodies.

15

What produces progesterone?

corpora lutea

16

Where is the sperm deposited.

Species dependent.
Vagina, cervex, or uterine body

17

Where does fertilization of the egg occur?

In the oviduct
(aka the uterine tube)

18

What facilitates the movement of sperm to the oviduct?

Increase in mucus production of the uterus during ovulation.

19

What are the three key reactions of fertilization?

Capacitation, Acrosome, and Cortical reactions.

20

Capacitation

Sperm
Shedding of the glycoprotein coat while in the uterine tube. Exposes reactors on the head of the sperm.

21

Acrosome

Sperm
Proteolytic enzymes are released from the acrosomal vesicle which starts digesting the outer portion of the zone pellucida so that the sperm can enter and start the cell division process.

22

Cortical

Oocyte
Prevents polyspermy. After one sperm breaks in there is a large increase in intercellular calcium. This changes cell surface ligands and creates a zone-block against other sperm.

23

When do the male and female pronuclei form?

Female - first meiotic division just before fertilization.
Male - Directly after fertilization.

24

When does the fertilized oocyte become a zygote?

Once female and male pronuclei form they fuse and mitotically divide. After this division the body is considered a zygote.

25

What is the role of the polar bodies?

Created during first meiotic division. Help with the first mitotic division.

26

What is the general rule of developmental potential?

As differentiation of the cells increase, the developmental potential of those cells decreases.

27

VERY GENERAL (5) important functions of fertilization

1. Restore the diploid karyotype.
2. Determination of chromosomal sex
3. initiation of cleavage
4. activation of the embryonic genome
5. activation of the epigenetic genome

28

The preformation theory

Every sperm contains a very tiny model of the animal that it will become.

29

The epigenesis theory

Based on actual fetal observations starting with Aristotle.
A landscape with factors pulling it different ways to create hills and valleys. Each cell is a ball that rolls down these hills to a different but mostly determined fate.

30

CRL

Crown-Rump Length
Used to judge the age of a domestic embryo, designed using years of empirical evidence.

31

Embryonic charts

Predict the stage of fetal development using age or CRL.

32

Hox genes

AKA Homeobox genes
Regulatory genes that help pattern the embryo with limb patterns, resp, GI, and nervous systems.
Where the genes are locate helps with this patterning.
First found in Drosophila.

33

ARTs

Assisted Reproductive Technologies
1. artificial insemination
2. oocyte transfer
3. nuclear (somatic) cell transfer - CLONING

34

Cloning process

AKA somatic or nuclear cell transfer
Enucleate an existing oocyte. Take adult somatic cell (mammary epithelial is most common) and fuse it with the oocyte to create a reconstructed oocyte.

35

Why does cloning only succeed 5-10% of the time?

Creation of the reconstructed oocyte skips all of the fertilization control steps. Cannot tell if it is viable until it fails.

36

What are some possible future applications of cloning?

Pet cloning
Endangered species cloning
Research animal cloning

37

Organogenesis

Development of organs, limbs, and organic body material

38

Teratogenesis

The development of congenital defects within an embryo.

39

Gametes

Haploid genetic material carriers - the sperm and the egg.

40

Zygote

The embryo in a 2-cell state. Diploid with both sets of genetic material after one mitotic division.

41

Morula

"Mulberry" - a group of large divided cells. Relatively random. Last totipotent stage.

42

Blastocyst

Cells have grown much smaller and a fluid filled cavity has grown in the center. Pleuripotent cells.

43

Folded tri-laminar embryo

3 layered embryo proper, after gastrulation. Multipoint cells.

44

Fetus

After approximately 35 days of growth. Unipotent cells.

45

Totipotent

Cells can be ANYTHING. This only is for the first few cell divisions.

46

Pluripotent

All the cell types that make up the embryo and the embryonic tissues (stem cells)

47

Multipotent

Mesoderm, Ectoderm, or Endoderm

48

Unipotent

Can become only one cell type

49

Types of cells in the blastocyst

Zona pellucida cells
Inner cell mass
trophoblasts

50

Inner cell mass of the blastocyst

Cells that will form the embryo proper and the embryonic tissues.

51

Trophoblasts

Will communicate with maternal endometrium and help form embryonic tissues

52

What tells the cells what to become, where to go, and how to develop?

Differentiation: what
Patterning: where
morphogenesis: how

53

Zona Pellucida

Layer of compact cells. Common from the oocyte until the blastocyst

54

Function of the fluid filled cavity of the blastocyst

Will "hatch" out of the blastocyst to interact with the endometrium and allow trophoblasts to interact as well.

55

When does the blastocyst "hatch?"

Species dependent - 3 to 8 days after fertilization occurs.

56

CT

Computed tomography
A broad array of angles of X-rays - the same density releases for x-rays apply here.

57

Clinical cross-sectional imaging

CT scans
Ultrasound
MRI

58

MRI

Magnetic Resonance Imaging
No x-rays used
Density rules of x-rays do not apply

59

Why is a muscle never completely relaxed or completely flexed?

Muscles never work in isolation! Agonists and Antagonists - their work always depends on what is around them.

60

How do feline claws retract and extend?

Two elastic ligaments attaches P3 and P2 - the shorter of which is from the distal middle phalynx to the ungual crest and the longer of which is from the proximal interpharyngeal joint to the ungual crest. When the digital flexors work, they do not move the distal phalanges because these elastic ligaments are so strong. Protrusion requires simultaneous action of the deep digital flexor and the digital extensors.

61

Syncytiotrophoblast

Cells unique to primates and some carnivores. Trophoblasts that are invasive to the maternal epithelium.

62

Epiblast

Sheet of the ICM that will turn into the embryo proper

63

Hypoblast

Sheet of the ICM that will be extra embryonic endoderm, including the yolk sac.

64

Bilaminar embryo

Inner cell mass of the blastocyst once it has formed the epiblast and the hypoblast.

65

Chorion

Forms the surfaces of the extra-embryonic tissues for the most part. Wraps entirely around the outside of the tissues. From the trophoblastic and epiblastic cells.

66

Extraembryonic ceolom

From the blastocyst fluid and cells. Most ventral to the fetus under the yolk sac.

67

Yolk Sac

From hypoblastic and trophoblastic cells. Most often used for fetal/maternal diffusion of metabolites. Just ventral to the embryo and will be included in many of the tube linings.

68

Allantois

Cavity and membrane from the hindgut of the embryo. Will eventually fuse with the chorion. Large cavities cranial and caudal to the embryo. Allantoic cavity helps maintain pressure on the fetus and uterus so that the fetus stays against the uterine wall, especially in species that lack syncytiotrophoblasts.

69

Amnion

Dorsal to the embryo. Formed by the closing of the chorion over the embryo. Amniotic fluid helps to protect and buffer the embryo, especially in small animal.

70

Chorio-allantois

Fluid filled and MASSIVE in large animals as a buffer to the embryo. This will contact the endometrium and turn into the placenta.

71

Are the extra-embryonic membranes of litters common between babies or separate?

Separate, each from their own oocyte. Embryonic membranes have the genetic material of the embryo.

72

Zonary Placenta

Chorionic villi aggregate into a large band around the placenta. Carnivores.

73

Cotyledonary Placenta

Chorionic villi aggregate into small round points in various areas of the placenta. Ruminants.

74

Diffuse Placenta

Chorionic villi spread evenly around the placenta. Pigs and horses.

75

Non-deciduate Placenta

No invasive syncytiotrophoblasts.
Need specialized systems to facilitate metabolic diffusion across membranes.
Porcine and equine - two distinct membranes separating blood supply
Ruminants - one highly specialized membrane separating blood supply.

76

Deciduate Placenta

Invasive - some endometrial layers must come out with the fetal membranes.
Carnivores - vessel next to vessel.
Primate and rodent - maternal blood mixes with trophoblastic cells. Simplest diffusion type.

77

Chorionic villi

A blood vessel rich region in the placenta. In most species, a mix of fetal and maternal vessels.

78

What will the fate of the yolk be?

Incorporated into tube structures
Yolk stalk becomes the first blood vessels in the chorionic villi.

79

How long after fertilization are the embryonic membranes created?

About 1-2 weeks depending on the species.

80

What events is the main determinant in a viable embryo?

Gastrulation!

81

On which side of the embryo does the primitive node form? Which way does the primative streak travel?

Caudal end and travels cranially, creating an axis of symmetry.

82

What happens to the epiblastic cells as the primitive streak passes?

Formation of a trilaminar embryo.
Epiblastic cells along the streak move inwards to create mesoderm. Endoderm is hypoblast (for the moment) and remaining epiblastic cells are ectoderm.

83

Where is the notochord? Where is the neural tube? Where are the neural crest cells?

All are on the ventral side of the embryo
Notochord is most ventral
Neural tube is dorsal to the notochord.
Neural crest cells are dorso-medial to the neural tube.

84

What phylum is monophyletic on the basis of having a notochord?

Chordata

85

What are neural crest cells?

Pluripotent cells from the dorsal edge of the neural groove.

86

What are some of the possible fates of neural crest cells?

Melanocytes
Spinal Ganglion
Adrenal Medulla
Autonomic neuron
Parts of the teeth
Parts of the heart
Sympathetic trunk ganglion
Abdominal autonomic plexus ganglion
dorsal and ventral roots of spinal cord
adrenal glands
viscera
spinal nerve
dorsal, lateral, and vetral furniculi

87

Neuropores

Open sections (caudal and rostral) as the neural groove closes. Incomplete closure is cause of a ton of birth defects.

88

Spina bifida

Caudal neuropore never closes
Especially common in manx cats with no tails
In humans, folate supplementation may help

89

Primary brain vesicles

3 rostral expansions of the neural tube: proencephalon, mesencephalon, and rhomboencephalon. Together they look like a Kong and form the primitive brains of lampreys and others like.

90

Secondary brain vesicles

Forms after primary. Definitive brain structural elements of advanced animals. Will normally fill with cerebral spinal fluid and become very small but remain present in the adult brain .

91

Hydrocephalus

If the flow of cerebral spinal fluid out of the brain vesicles is blocked or hindered for some reason, spaces will grow enormous.
Genetic factors, intrauterine or perinatal infections or bleeding in the brain can all cause.

92

Neural canal

Normal adult formation out of the ventricular system (residual fluid filled vesicle spaces)

93

Ventricular zone

Of the spinal cord, on edges of the central canal. Mitotically active cells that give rise to new neuroblasts.

94

Intermediate zone

Of the spinal cord, also called the mantle. Gray matter. Between white matter and the ventricular zone.

95

Marginal zone

Outer portion of the spinal cord. White matter.

96

Basal plate

Migration of the neuroblasts of the ventricular zone. Will become the ventral horn sensory and motor neurons.

97

Alar plate

Migration of the neuroblasts of the ventricular zone. Will become the dorsal horn sensory and motor neurons.

98

Paraxial mesoderm

Mesoderm immediately lateral to the neural tube. Becomes the vertebrae.

99

Intermediate mesoderm

Becomes the reproductive tract.

100

Lateral mesoderm

Limbs and supportive CT of tubular organs.
Dorsal = somatic (body/skin)
Ventral = splanchnic (organs)

101

Teratology

Study of congenital defects (aka developmental defects)

102

Why do mutations occur?

Negative interaction between the genetic makeup of the embryo and the environment (internal or external).

103

Polydactyly

Extra fingers

104

Polymelia

Extra limbs

105

Atresia ani

No external anus
Very common in swine

106

Teratogens

extrinsic teratogenic agents or factors with the ability to cause a defect

107

How many animals have developmental defects?

Reported - 1% to 6%
May be higher - necropsies are not done on every stillborn animal.

108

Syndrome

A defect that affects multiple systems in the body.

109

Schistosomus reflexus

Seen in ruminants - the body looks flipped inside out. Spinal inversion, abdominal visceral herniation, ankylosis (the fusion of the joints), limb malposition, pulmonic and diaphragmatic hypoplasia.

110

Critical period

The time during which teratogens have the greatest effect on the embryo, usually between 3 to 5 weeks after FERTILIZATION (not breeding). This is after the totipotent/pleuripotent stage of the embryo where it can either regenerate or just die - the cells are now committed to organs. But, it is before the organ systems are reasonably stable.

111

Gestastional suseptibility

Dosage or duration of exposure to the teratogen.

112

Major causes of intrinsic teratogenesis

Chromosomal abnormalities (translocations, inversions or deletions). Worst insult.
Mutations - in nt sequences.

113

Major classes of teratogenic agents (and an example of each)

1. Infectious agents - especially viruses
(Feline panleukopenia and hydrocephalus)
2. Plant toxins - especially alkaloids
(Veratrum californium - cyclopia)
3. Drugs
(Streptomycin - ototoxicity and deafness)
4. Other
(Ionizing radiation, man-made toxins, metabolic disturbances - vitamins - or physical factors - hyperthermia, too much fluid, etc.)

114

Cyclopia

Also called holoprosencephaly. Complete or partial fusion of the orbits from incomplete closure of the rostral neuropore.
Common in sheep that are exposed to Veratrum californicum (false hellebore or skunk cabbage which contains cyclopamine/jervine alkaloids) during the critical period
Causes inhibition of the SHH signalling pathway
Can theoretically be born alive, but SHH also affects the lung and the heart - is this a defect or a syndrome?

115

Albinism

Intrinsic. Defect in tyrosinase affects melatonin sythesis.

116

Myotonia Congenita

Intrinsic. Chlorine channel defect in many species but most famous for "fainting goats."

117

Malignant Hyperthermia

Intrinsic. Arg-Cys mutation affects ryanodine receptor in pigs and humans.

118

Vitamin A deficiency

Extrinsic. Responsible for ocular defects in cattle.

119

Copper deficiency.

Extrinsic. Responsible for the destruction of white matter of the cerebrum in lambs.

120

Laceration

Deep cut or tear in the skin or the flesh

121

Hemorrhage

Escape of blood from a vessel

122

Denervation

Loss of nerve supply due to disease, toxin, physical injury, etc.

123

Paralysis

Loss in ability to move and often to feel.

124

Contracture

Shortening/hardening of a muscle/tendon

125

Agonists

Two things that work in the same way or together

126

Antagonists

Two things that work in the opposite ways or against each other.

127

How should you orient a needle while giving an IM injection in the thigh of a small dog?

Caudally.
The sciatic nerve runs parallel to the groove created by the semitendonosis and the biceps femoris. If you aim cranially it is possible to hit this by going through the semitendonosis. Caudally directs the needle and liquid away from the nerve

128

Why are there so many extensors of the hip?

For propulsion! and they are especially large in speedy dogs.

129

Medial/Lateral rotation of the limb is defined by?

The cranial surface of the limb

130

What important structure of the dog hip does the cat does not have?

The sacrotuberous ligament

131

Which of the menisci of the stifle is more easily damaged?

Medial meniscus, as it is strongly attached to the medial collateral ligament. If there is a knee injury this meniscus has less room to move and so might get torn.

132

What elements stabalize the hip joint?

Ball and socket joint
Fibrous joint capsule
Large bulk of muscle around the hip joint
Ligament of the femoral head and transverse ligament

133

How does a cruciate tear usually occur in a dog?

Usually rotation while extending the limb. Usually damage occurs only to the cranial cruciate or the cranial and caudal cruciate but NOT just to the caudal cruciate.

134

How are the cruciate joints named?

For where they attach to the tibia

135

Drawer test

Measures the cranial movement of the tibia relative to the femur. Positive = damaged cranial cruciate ligament.

136

Falciform ligament

Just below the linea alba in the abdominal cavity.

137

Ligaments with roles in IVDD

Intervertebral discs (nucleus pulposus or annulus fibrosus), ventral/dorsal longitudinal ligaments, and intercapital ligaments.